The generation of hydrogen has been commonly performed for over 100 years through the hydrolysis of hydrides or other solid reactants. Previously, hydrogen generation has been advanced by employing the adiabatic hydrolysis and thermal decomposition of the chemical hydride in a portable lightweight unit. Such hydrogen generation technologies are characterized by heating the chemical hydride to a predetermined temperature. The chemical hydride is preferably lithium aluminum tetrahydride (LiAlH.sub.4) and the predetermined temperature is greater than about 100.degree. C. Only after the chemical hydride reaches the predetermined temperature is water supplied for hydrolysis of the chemical hydride.
With respect to such a portable hydrogen generator, it may be more suitable to employ a reactant other than water to avoid some of the requirements when water is utilized. In particular, use of water requires a controlled pump mechanism that pumps the water from the water supply for reaction with the chemical hydride at pressures greater than ambient atmospheric. Furthermore, as just noted, in connection with proper preparation for reaction with the water, the chemical hydride must be heated to a high temperature before allowing the reaction to occur. Such a system may only be operated above 0.degree. C. This results in additional heating materials or components in order to implement a fully operational unit that outputs the desired hydrogen gas. Such a prior art hydrogen generator also has a buffer to handle excess hydrogen generated when the apparatus is shut down and can also serve to smooth hydrogen demand swings during normal operation. It is preferred that this system have a restart capability after a long (days to weeks) shutdown period. In considering these aspects, it would be advantageous to provide a hydrogen generating apparatus that is fully operational and satisfies all specified power demands, or other performance criteria, while eliminating one or more of the afore-noted hardware requirements that must be incorporated when water is utilized as the reactant with the chemical hydride.